The invention relates to a process for production of an object consisting of at least two parts movable relative to each other, one of which or a portion thereof is substantially enclosed within the other.
Specifically, the invention is addressed to a process for production of such an object wherein one or more loose members are enclosed between the two parts of the object.
In the production of such objects, the placement of the members between the parts presents a difficult problem.
This problem has now been solved by making one of the parts in at least two separate pieces, placing these pieces against each other and holding them in the correct position in relation to the other part, setting up a high energy beam welding means such as a laser or electron beam over the parting line between the two pieces, and putting it in operation, at least the said two pieces being moved bodily in order to move the parting line along the energy beam and weld the two pieces together, the members being emplaced at the time of moving the two pieces of the one part together into the correct position in relation to the other part.
German Letters of Disclosure No. 2,712,539 do disclose a process for production of a self-aligning friction bearing consisting of a sleeve having a spherical outer surface inside an annular casing with a matching spherical inner surface, the casing being composed of two pieces which are welded to each other around the sleeve by means of a stationary electron beam welding means aimed at the parting line between the said two pieces, the sleeve and the casing being rotated bodily together.
In particular, the process according to the invention may be applied to the production of objects the parts of which are annular, like sealing rings or races of antifriction bearings, the one part being made in two pieces such that the parting line lies in a plane perpendicular to the axis of rotation of the ring. The part made in two pieces may be the inner part, in which case the outer part is provided with an opening passing radially through it and located over the parting line in assembled condition, while the high energy beam welding means is placed over the outer end of the opening so that the energy beam reaches the parting line through the opening, and the two pieces of the inner part are bodily set in rotation together while the outer part is held stationary.
This latter form of the process according to the invention is especially advantageous for the production of antifriction bearings having two rows of rolling members, in which case the innermost race, constituting the inner part, is made in two pieces such that the parting line is located between the rows, so that then the inner race may be made in two parts that when these parts are brought up against each other, a prestress is applied to the rolling members.
In order to prevent spatters from sticking between the parts during the welding, and/or damage from being done by the heat of the energy beam, a small tube may be arranged in the opening in the other part, its bottom end extending to above the parting line. Preferably the tube, which is removable, consists of a material capable of catching and retaining spatters that occur during welding.
Alternatively, on opposed sides of the opening in the outermost part, two annular discs substantially parallel to each other may be attached by their outer peripheries to the inner surface of the outermost part, the inner peripheries of these discs being located on opposed sides of the parting line, over the outer surface of the innermost part. In this way, support may also be provided for the cages.
By the process according to the invention, it is in particular a very simple matter to produce an antifriction bearing, which bearing may be a full prestressed bearing unit, so that locking means such as a ring with lock nut may be dispensed with. Furthermore, a bearing with tapered rolling members may be obtained in which the inner race is provided with outer shoulders only, thus eliminating the machining required to make the inner shoulders.